1. Technical Field of the Invention
This invention relates to telecommunication systems and, more particularly, to a system and method of automatic roaming analysis (ARA) for dialing abbreviated numbers in a wireless intelligent network (WIN), wherein a mobile subscriber can enter abbreviated numbers for originating calls regardless of the subscriber""s location in the network.
2. Description of Related Art
For today""s users of radio telecommunications services (also commonly known as mobile subscribers), short digit dialing (SDD) or speed dialing is a distinct advantage over conventional dialing where all digits comprising the complete telephone number of a called party need to be entered. Almost all available mobile phones have an abbreviated dialing memory in order to facilitate the dialing of frequently used numbers.
The conventional method to use abbreviated dialing, where the number stored in the memory is read from the memory as such, is typically useful only in a portion of a radio telecommunications network such as, for example, a home network portion associated with the mobile subscriber. Clearly, such a limitation would severely reduce the usefulness of the SDD feature to a roaming mobile subscriber.
Unfortunately, commonly available current solutions that attempt to address this limitation in the conventional abbreviated dialing are not adequate or satisfactory because they are merely extensions of the memory-based scheme. For example, assume that a telephone number in Country X, say, 90 123456 is entered into the abbreviated dialing memory of a mobile phone. Obviously, it is returned in the same form, when it is read out from the memory for effectuating abbreviated dialing. If the subscriber is traveling in Country Y and from there wants to place a call to the same telephone number in Country X, the subscriber cannot use the same abbreviated dialing facility, because the subscriber now has to enter the number including applicable international access codes. Thus, in this example, the subscriber has to dial the number 099 358 0 123456. Accordingly, for the same telephone number in Country X (local number), the subscriber would have to program a different number for calls originated from each country or region located within the coverage area of the network. It can be readily appreciated that this scheme requires a large memory for the storage of numerous variations of a single local number. Further, the mobile subscriber has to remember the abbreviated memory locations for all the variations of the same number, so that only the right memory location is read out, depending on the country or region in which the subscriber is located while placing the call.
Moreover, the problems associated with the conventional abbreviated dialing methods are exacerbated in radio telecommunications networks that cover larger number of countries, thereby greatly reducing the usefulness of the feature to international travelers.
Accordingly, based upon the foregoing discussion, it should be readily appreciated that in order to overcome the deficiencies and shortcomings of the existing solutions, it would be advantageous to have a method and system for providing an intelligent automatic roaming analysis that enables a roaming mobile subscriber to use abbreviated dialing regardless of the location in a radio telecommunications network. The present invention provides such a method and system.
In one aspect, the present invention is related to a method of supporting a short digit dialing (SDD) service for a roaming mobile subscriber in a radio telecommunications system of the type which includes a plurality of visited exchanges. Each visited exchange is provided with an identity indicator (MSCID). For a visited exchange outside the home area (called visited service area), it is also provided with a type designation. A home network is included which comprises at least a visited exchange, a Home Location Register (HLR), and a Service Control Point (SCP), either coupled or not to the HLR. The SCP""s database includes a subscriber data set and an operator service data set, and a service execution portion relating to the short digit dialing service. The method comprises populating the subscriber data set with at least an International Access Code (IAC), a National Access Code (NAC), a Country Code (CCD) and an Area Code (ACD) for the home network, in addition to the MSCIDs of the exchanges therein. The method also involves populating the operator service data set at least with a visited exchange""s type that serves a visited service area, and an IAC, an NAC, a CCD and an ACD, and an MSCID for the visited exchange of the visited service area. When a mobile subscriber dials an abbreviated number from a visited exchange, a determination is made in the SCP whether the mobile subscriber is located in a visited exchange. If so, the type designation of the visited service area exchange is determined. A call treatment instruction may be received in the SCP either from the HLR or from the visited exchange. The call treatment instruction preferably includes at least the MSCID of the exchange. The SCP performs a translation process on the abbreviated number to generate a translated number (TN). Then the SCP determines if the mobile subscriber is roaming. Based on the type designation of the visited exchange, a called party number (B-number) is selectively rebuilt using the TN in the SCP. The originated call is selectively terminated using the B-number.
In another aspect, the present invention is directed to a radio telecommunications network system covering a geographic area comprised of a plurality of service areas, each of which is served by a mobile switching center (MSC) having an identification indicator (MSCID). The system includes an SCP for supporting a customer service data set associated with a mobile subscriber, an operator service data set for global definition of the visited MSCs, and roaming detecting means for detecting whether the mobile subscriber is visiting the visited service area. The customer service data set includes a first plurality of telephone number code portions associated with an MSC serving a home service area of the mobile subscriber. The operator service data set includes a second plurality of telephone code portions associated visited MSC serving a visited service area and a type portion for designating a type parameter for the visited MSC. In the network system, there are means available to the mobile subscriber for entering a short digit dial number associated with a called party""s telephone number. Also included in the network system is an HLR that may be operably coupled to the SCP. The HLR provides a call treatment instruction in response to a service query from the visited MSC. The SCP executes a service portion in response to the call treatment instruction transited through the HLR or directly from an exchange when the mobile subscriber is located in the visited service area and enters the short digit dial number for the called party. The service portion returns an indication with respect to the called party which typically includes a complete B-number for the called party. The subscriber""s call is then terminated using the B-number in a conventional manner.
In a yet further aspect, the present invention is directed to a radio telecommunications network system that enables a mobile subscriber roaming in visited exchange to originate a call by entering an abbreviated number. The network system is comprised of a home service area, with one or more exchanges, that is served by an SCP and possibly an HLR. Also included in the network system is a visited service area having one or more exchanges. All exchanges have an identity indicator, while those in the visited service area have a type parameter in addition. The network system supports an SDD scheme for the mobile subscriber whereby the subscriber can originate calls from the visited exchanges in the home service area or the visited service area using an abbreviated number. The network system includes first data set means for maintaining the mobile subscriber""s subscription information data and a first plurality of digit portions. The digit portions are selectively prepended for a call originated by the mobile subscriber from the home service area by entering an abbreviated number for a called party. Also included is second data set means for maintaining a list of the identity indicators, type parameters and a second plurality of digit portions for the visited exchanges in the visited service area. There are detecting means in the SCP for detecting if the mobile subscriber is located in a visited exchange of the visited service area. Responsive to the detecting means, when a call is placed by the mobile subscriber by entering an abbreviated number in the visited exchange of the visited service area, there are Automatic Roaming Analysis (ARA) means in the SCP for converting the abbreviated number, wherein the conversion is based on the visited exchange""s type and results into a called party""s number. There are also means for transmitting the called party""s number to the visited exchange so that the call is routed to the called party.